» Fusion-fission hybrid system to eliminate waste produced by nuclear power plants

Fusion-fission hybrid system to eliminate waste produced by nuclear power plants

Published: Wednesday, January 28, 2009, 13:37 [IST]

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Washington, Jan 28 (ANI): Physicists at the University of Texas at Austin, US, have designed a new system that, when fully developed, would use a hybrid of nuclear fusion-fission to eliminate most of the transuranic waste produced by nuclear power plants, and contribute to a carbon-free energy future.

The invention could help combat global warming by making nuclear power cleaner and thus a more viable replacement of carbon-heavy energy sources, such as coal.

"We have created a way to use fusion to relatively inexpensively destroy the waste from nuclear fission," said Mike Kotschenreuther, senior research scientist with the Institute for Fusion Studies (IFS) and Department of Physics.

"Our waste destruction system, we believe, will allow nuclear power-a low carbon source of energy-to take its place in helping us combat global warming," he added.

The physicists' new invention could drastically decrease the need for any additional or expanded geological repositories for toxic nuclear waste.

"Most people cite nuclear waste as the main reason they oppose nuclear fission as a source of power," said Swadesh Mahajan, senior research scientist.

The scientists propose destroying the waste using a fusion-fission hybrid reactor, the centerpiece of which is a high power Compact Fusion Neutron Source (CFNS) made possible by a crucial invention.

The CFNS would provide abundant neutrons through fusion to a surrounding fission blanket that uses transuranic waste as nuclear fuel.

The fusion-produced neutrons augment the fission reaction, imparting efficiency and stability to the waste incineration process.

The scientists' waste destruction system would work in two major steps.

First, 75 percent of the original reactor waste is destroyed in standard, relatively inexpensive LWRs. This step produces energy, but it does not destroy highly radiotoxic, transuranic, long-lived waste, what the scientists call "sludge."

In the second step, the sludge would be destroyed in a CFNS-based fusion-fission hybrid.

The hybrid's potential lies in its ability to burn this hazardous sludge, which cannot be stably burnt in conventional systems.

"To burn this really hard to burn sludge, you really need to hit it with a sledgehammer, and that's what we have invented here," said Kotschenreuther.

The process would ultimately reduce the transuranic waste from the original fission reactors by up to 99 percent. Burning that waste also produces energy.

The CFNS is designed to be no larger than a small room, and much fewer of the devices would be needed compared to other schemes that are being investigated for similar processes.

According to the scientists, in combination with the substantial decrease in the need for geological storage, the CFNS-enabled waste-destruction system would be much cheaper and faster than other routes. (ANI)